Container-closure assemblies of the type to which the present invention relate typically comprise a container made of plastic having a nozzle portion with a puncturable diaphragm defining a discharge opening and a closure or cap having a piercing element selectively engageable in the diaphragm to form a discharge opening when it is desired to remove the contents of the container. Container-closure assemblies of this general type are not new per se. For example, the patents listed below show container-closure assemblies of this general type:
1. John R. O'Meara UNIT DOSE CONTAINER WITH CAPTIVE CAP U.S. Pat. No. 4,765,518 Issue Date: Aug. 23, 1988
2. John R. O'Meara CHILD RESISTANT CAP U.S. Pat. No. 4,867,326 Issue Date: Sep. 19, 1989
3. John R. O'Meara CONTAINER AND CLOSURE ASSEMBLY U.S. Pat. No. 4,884,703 Issue Date: Dec. 5, 1989
4. John R. O'Meara UNIT DOSE ASSEMBLY U.S. Pat. No. 5,042,690 Issue Date: Aug. 27, 1991
5. John R. O'Meara UNIT DOSE ASSEMBLY U.S. Pat. No. 5,052,589 Issue Date: Oct. 1, 1991
6. Deusen U.S. Pat. No. Issue Date:
These patents have certain disadvantages and drawbacks. It has been found that a drawback in these prior assemblies is a phenomenon referred to as "spurting" which results in loss of product from the container during the diaphragm piercing step. More specifically, it has been found that the force needed to disengage the locking rib in the prior art assemblies to move the cap downwardly in a direction to pierce the diaphragm requires the user to exert a strong grip on the container or squeeze it excessively to produce a reaction force counteracting the applied force needed to puncture the diaphragm. Further, it has been found that in the assemblies where the piercing element is on another portion of the closure, unless it is applied in a truly axial direction, the piercing element tends to engage the thick wall portion of the nozzle surrounding the diaphragm which increases the force necessary by the user in the puncturing process.